I want to send mail with a bash script.
I look on the internet what I have to do.
I installed exim4 and mailutils.
than I do sudo echo "Yay - SMTP works" | mail -s "Test email" mail-address"
but the mail wasn't sent.
I find this sudo dpkg-reconfigure exim4-config
but I don't know what I must fill in this.
I find also netstat -ano |grep :25 and
the output is

 tcp   0  0 127.0.0.1:25   0.0.0.0:*  LISTEN  off (0.00/0/0)
 tcp6  0  0 ::1:25         :::*       LISTEN  off (0.00/0/0)

I may not be able to help you, but please post the following basic information:
1) Operating System and version.
2) What Shell you use.
3) Whether mail within the computer works.

I suppose your MTA (exim) is not correctly configured. How this has to be done depends so much on your network and its configuration that it is not possible to give some generalized answer.

Please answer specific questions and we can answer specifically.

In the meantime you might be interested in a little introduction about how the mail system works in general i wrote a few days ago.

I hope this helps.

bakunin